Engineering Wonders of the World
Volume I

THE SUEZ CANAL. 251 More interesting still is the actual connected with the widening scheme, this, the amount of excavation carried out in 1904 totalled 1,689,275 cubic yards of earth- work, and 1,863,646 cubic yards of dredg- ing. The following year saw the removal of 1,570,476 cubic yards of earthwork and 914,316 cubic yards of dredging ; while, in 1906, 3,255,271 cubic yards were dredged, and some 1,829,564 cubic yards of earth, removed. The ballast above the water-level is removed by manual labour, terraces being cut into the banks, along which temporary railway tracks are laid. From the water-level to the pre- scribed depth dredgers of various types are employed, some cutting their way into the bank and dumping the excavated material, by means of overhead transporters, upon the bank, and others discharging it into lighters. The ballast consists, for the most part, of sand, the rock encountered being approximately four per cent, of the total amount. In the dredging of the navigation channel itself the type of dredger with floating conduit is most favoured, the excavated material being dis- charged through the pipe, usually where the bank is so low that its height may be increased to advantage. To accomplish this work the Company em- ploy the largest and finest dredgers in the world. The newer ones are capable of dredging to a depth of 36 feet. One of their most remarkable dredging ma- chines is the Dérocheuse, which is able to remove even rock. It was built by Messrs. Lobnitz and Company of Renfrew, and is fitted with rock-breaking rams. These rams, which are in principle simply huge chisel-pointed ham- mers, weighing four tons each, are raised by hydraulic power and allowed to fall through from 10 to 20 feet. There are five on each side of the well, and an ordinary bucket- dredge, working between them, raises the rock broken by the hammers. Among the Com- A Rock- breaking Dredger. work For pany’s extensive plant are a 60-ton floating sheerlegs and a 12-ton floating crane. For the purpose of docking their vessels quickly they have at Port Said a 3,000-ton floating dock. A glance at the following table shows the improvement which has already been effected in the waterway since open :— it was Width at Bottom. 72 ft. 147 ft. first declared Width at Water- level. 150 to 300 ft. 240 to 360 ft. Depth. When opened..... 26 ft. At the present time 34£ ft. As a matter of fact, when the Canal was opened the depth of 26 feet aimed at was not attained for the whole length of the channel. In some places it did not exceed 20 feet, nor the width at bottom 60 feet. At short intervals “ gares,” or sidings, where vessels proceeding in opposite directions are able to pass each other, have been cut. Twelve were completed in 1904, and plans were then prepared for the construction of twenty- one others, principally near the lakes. Each of these gares will have a length of 2,460 feet, and approaches at either end of 984 feet. At a gare the width at bottom of the Canal is 180 feet, and at water-level over 300 feet, the width of the gare itself being 93 feet. One of the greatest dangers with which, the authorities have to contend is the stranding or foundering of vessels, whereby the pas- sage through the Canal is blocked. In the year 1905 such accidents averaged 1'7 per cent, of vessels passing through, whereas in 1885 the average was 4’3 per cent. This improvement is attributable to the widening of the waterway, and to the improved facilities now in vogue for enabling vessels to proceed. In 1905, however, the resources of the authorities were severely taxed by the foundering of the steamer Chatham through collision with another vessel. The ship sank in the centre of the channel, tying “ Gares,’ or Sidings. Stranded or Sunken Vessels.